Bacterial enzyme inhibitors

ABSTRACT

Compounds of formula (I) are antibacterial agents: wherein: Z is —N(OH)CH(═O) or —C(═O)NH(OH); R 1  represents hydrogen, methyl or trifluoromethyl or, except when Z is a radical of formula —N(OH)CH(═O), a hydroxy, halo or amino group; R 2 , R 3  and R 4  independently represents hydrogen or a group R 10 -(D) n -(ALK) m - wherein R 10 , D, n, m and ALK are as defined in the claims; or R 3  and R 4  taken together with the nitrogen atom to which they are attached form an optionally substituted monocyclic heterocyclic ring containing from 5 to 7 ring atoms, one of which is the nitrogen atom to which R 4  and R 5  are attached and the remaining ring atoms being selected from compatible combinations of carbon, oxygen, sulfur and nitrogen.

This invention relates to hydroxamic acid and N-formyl hydroxylaminecompounds which inhibit the activity of the bacterial enzyme known aspeptide deformylase. Since bacterial growth is known to be inhibited byinhibitors of peptide deformylase, the compounds of the invention areexpected to include antibacterial agents.

BACKGROUND TO THE INVENTION

The compounds of the invention are inhibitors of bacterial polypeptidedeformylase (PDF; EC 3.5.1.31).

All ribosome-mediated synthesis of proteins starts with a methionineresidue. In prokaryotes, the methionyl moiety carried by the initiatortRNA is N-formylated prior to its incorporation into a polypeptide.Consequently, N-formylmethionine is always present at the N-terminus ofa nascent bacterial polypeptide. However, most mature proteins do notretain the N-formyl group or the terminal methionine residue.Deformylation is required prior to methionine removal, since methionineaminopeptidase does not recognise peptides with an N-terminalformylmethionine residue (Solbiati et al., J. Mol. Biol. 290: 607-614,1999). Deformylation is, therefore, a crucial step in bacterial proteinbiosynthesis and the enzyme responsible, PDF, is essential for normalbacterial growth. The gene encoding PDF (def) is present in allpathogenic bacteria for which sequences are known (Meinnel et al., J.Mol. Biol, 266: 939-49, 1997). Although a deformylase homologue hasrecently been cloned from the mitochondria of human cells (Giglione et.el. EMBO Journal, 19, 5916-5929, 2000) it has not been shown to befunctional, and its relevance is unknown. Since a number of currentlyused antibiotics are known to act on both bacteria and mitochondria, PDFis still considered to be a target for antibacterial chemotherapy (for areview see Giglione et al., Mol Microbiol., 36: 1197-1205, 2000).

The isolation and characterisation of PDF has been facilitated by anunderstanding of the importance of the metal ion in the active site(Groche et al., Biophys. Biochem. Res. Commun., 246: 324-6, 1998). TheFe²⁺ form is highly active in vivo but is unstable when isolated due tooxidative degradation (Rajagopalan et al., J. Biol. Chem. 273: 22305-10,1998). The Ni²⁺ form of the enzyme has specific activity comparable withthe ferrous enzyme but is oxygen-insensitive (Ragusa et al., J. Mol.Biol. 1998, 280: 515-23, 1998). The Zn²⁺ enzyme is also stable but isalmost devoid of catalytic activity (Rajagopalan et al., J. Am. Chem.Soc. 119: 12418-12419, 1997).

Several X-ray crystal structures and NMR structures of E. coli PDF, withor without bound inhibitors, have been published (Chan et al.,Biochemistry 36: 13904-9, 1997; Becker et al., Nature Struct. Biol. 5:1053-8, 1998; Becker et al., J. Biol. Chem. 273: 11413-6, 1998; Hao etal., Biochemistry, 38: 4712-9, 1999; Dardel et al., J. Mol. Biol. 280:501-13, 1998; O'Connell et al., J. Biomol. NMR, 13: 311-24, 1999),indicating similarities in active site geometry to metalloproteinasessuch as thermolysin and the metzincins.

The substrate specificity of PDF has been extensively studied (Ragusa etal., J. Mol. Biol. 289: 1445-57, 1999; Hu et al., Biochemistry 38:643-50, 1999; Meinnel et al., Biochemistry, 38: 4287-95, 1999). Theseauthors conclude that an unbranched hydrophobic chain is preferred atP1′, while a wide variety of P2′ substituents are acceptable and anaromatic amide substituent may be advantageous at the P3′ position.There have also been reports that small peptidic compounds containing anH-phosphonate (Hu et al., Bioorg. Med. Chem. Lett., 8: 2479-82, 1998) orthiol (Meinnel et al., Biochemistry, 38: 4287-95, 1999; Huntingdon etal., Biochemistry, 39: 4543-51, 2000; Wei et al, J. Combinatorial Chem.,2: 650-57, 2000) metal binding group are micromolar inhibitors of PDF.Peptide aldehydes such as calpeptin (N-Cbz-Leu-norleucinal) have alsobeen shown to inhibit PDF (Durand et al., Arch. Biochem. Biophys., 367:297-302, 1999). Recently, the naturally occurring hydroxamic acidantibiotic actinonin, for which the target of its antibacterial activitywas previously unknown, was shown to be a potent inhibitor ofpolypeptide deformylase (WO 99/39704, and Chen et al, Biochemistry, 39:1256-62, 2000). Examples of non-peptidic PDF inhibitors with carboxylicacid (Green et al., Arch. Biochem. Biophys. 375: 355-8, 2000; Jayasekeraet al., ibid., 381: 313-6, 2000) or hydroxamic acid (Apfel et al., J.Med. Chem., 43: 2324-31, 2000) metal binding groups are also known.

It has been reported that PDF is present in eukaryotic parasites such asPlasmodium falciparum (Meinnel, Parasitology Today, 16: 165-8, 2000).Those authors also found evidence for the presence of PDF in otherparasites of humans, such as the kinetoplastid protozoan parasitesTrypanosoma brucei and Leishmania major. Based on these findings, it isanticipated that the hydroxamic acid and N-formyl hydroxylaminecompounds with which this invention is concerned have antiprotozoalactivity, and are useful in the treatment of malaria and other protozoaldiseases.

Several patent applications describe antibacterial hydroxamic acid andN-formyl hydroxylamine agents whose activity has been attributed toinhibition of PDF. These publications include our copendingInternational patent applications nos. WO 99/39704, WO 99/59568, WO00/35440, WO 00/44373, WO 00/58294 and WO 00/61134, as well as WO01/40198 (Aventis), WO 01/44179 (Versicor), WO 01/44178 (Versicor), andWO 01/38561 (Questcor).

Further, actinonin is a naturally occurring antibacterial agent having ahydroxamic acid group, and certain derivatives of actinonin are alsoknown to have antibacterial activity. (see for example Bouboutou et al,Colloq. INSERM (1989) 174 (Forum Pept. 2^(nd), 1988), 341-4; Lelevre et.al. Pathol. Biol. (1989), 37(1), 43-46; Broughton et. al. J. Chem. Soc.Perkin Trans. 1 (1975) (9), 857-60. The antibacterial activity ofactinonin has been shown to be due, at least in part, to inhibition ofPDF (WO 99/39704 and other publications).

BRIEF DESCRIPTION OF THE INVENTION

This invention is based on the discovery of a class of hydroxamic acidand N-formyl hydroxylamine derivatives which are inhibitors of theactivity of PDF. Compounds in that class are therefore expected to haveantibacterial activity. The class includes novel structures which formpart of the invention. Also within the scope of the invention is amethod of identifying antibacterial agents from within the class of PDFinhibitors of the invention.

DETAILED DESCRIPTION OF THE INVENTION

According to the invention there is provided a compound of formula (I),or a salt or hydrate thereof:

wherein:

-   Z represents a radical of formula —N(OH)CH(═O) or formula    —C(═O)NH(OH);-   R₁ represents hydrogen, methyl or trifluoromethyl or, except when Z    is a radical of formula —N(OH)CH(═O), a hydroxy, halo or amino group-   R₂ represents hydrogen or a group R₁₀-(D)_(n)-(ALK)_(m)- wherein    -   R₁₀ represents an optionally substituted C₁-C₆ alkyl, C₂-C₆        alkenyl, C₂-C₆ alkynyl, cycloalkyl, aryl, or heterocyclyl group        and    -   ALK represents a straight or branched divalent C₁-C₆ alkylene,        C₂-C₆ alkenylene, or C₂-C₆ alkynylene radical, and may be        interrupted by one or more non-adjacent —NH—, —O— or —S—        linkages,    -   D represents —NH—, —O— or —S—, and    -   n is 0 or 1;-   R₃ and R₄ independently represent hydrogen or a group    R₁₀-(D)_(n)-(ALK)_(m)- as defined for R₂, or-   R₃ and R₄ taken together with the nitrogen atom to which they are    attached form an optionally substituted monocyclic heterocyclic ring    containing from 5 to 7 ring atoms, one of which is the nitrogen atom    to which R₄ and R₅ are attached and the remaining ring atoms being    selected from compatible combinations of carbon, oxygen, sulfur and    nitrogen.

In another aspect, the invention provides a method for the treatment ofbacterial infections in humans and non-human mammals, which comprisesadministering to a subject suffering such infection an antibacteriallyeffective dose of a compound of formula (I) as defined above.

In a further aspect of the invention there is provided a method for thetreatment of bacterial contamination by applying an antibacteriallyeffective amount of a compound of formula (I) as defined above to thesite of contamination.

The compounds of formula (I) as defined above may be used ascomponent(s) of antibacterial cleaning or disinfecting materials.

As used herein the term “(C₁-C₆)alkyl” means a straight or branchedchain alkyl moiety having from 1 to 6 carbon atoms, including forexample, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,sec-butyl, t-butyl, n-pentyl and n-hexyl.

As used herein the term “(C₂-C₆)alkenyl” means a straight or branchedchain alkenyl moiety having from 2 to 6 carbon atoms having at least onedouble bond of either E or Z stereochemistry where applicable. The termincludes, for example, vinyl, allyl, 1- and 2-butenyl and2-methyl-2-propenyl.

As used herein the term “C₂-C₆ alkynyl” refers to straight chain orbranched chain hydrocarbon groups having from two to six carbon atomsand having in addition one triple bond. This term would include forexample, ethynyl, 1-propynyl, 1- and 2-butynyl, 2-methyl-2-propynyl,2-pentynyl, 3-pentynyl, 4-pentynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl and5-hexynyl.

As used herein the term “cycloalkyl” means a saturated alicyclic moietyhaving from 3-8 carbon atoms and includes, for example, cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl.

As used herein the term “aryl” refers to a mono-, bi- or tri-cycliccarbocyclic aromatic group, and to groups consisting of two covalentlylinked monocyclic carbocyclic aromatic groups. Illustrative of suchgroups are phenyl, biphenyl and napthyl.

As used herein the term “heteroaryl” refers to a 5- or 6-memberedaromatic ring containing one or more heteroatoms; Illustrative of suchgroups are thienyl, furyl, pyrrolyl, imidazolyl, benzimidazolyl,thiazolyl, pyrazolyl, isoxazolyl, isothiazolyl, triazolyl, thiadiazolyl,oxadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl.

As used herein the unqualified term “heterocyclyl” or “heterocyclic”includes “heteroaryl” as defined above, and in particular means a 5-7membered aromatic or non-aromatic heterocyclic ring containing one ormore heteroatoms selected from S, N and O, including for example,pyrrolyl, furanyl, thienyl, piperidinyl, imidazolyl, oxazolyl,isoxazolyl, thiazolyl, thiadiazolyl, pyrazolyl, pyridinyl, pyrrolidinyl,pyrimidinyl, morpholinyl, piperazinyl, indolyl, morpholinyl,benzofuranyl, pyranyl, isoxazolyl, benzimidazolyl, methylenedioxyphenyl,maleimido and succinimido groups.

Unless otherwise specified in the context in which it occurs, the term“substituted” as applied to any moiety herein means substituted with upto four substituents, each of which independently may be (C₁-C₆)alkyl,phenyl, benzyl, (C₁-C₆)alkoxy, hydroxy, mercapto, (C₁-C₆)alkylthio,amino, halo (including fluoro, chloro, bromo and iodo), cyano,trifluoromethyl, nitro, —COOH, —CONH_(2,) —COR^(A), —COOR^(A),—NHCOR^(A), —CONHR^(A), —NHR^(A), —NR^(A)R^(B), or —CONR^(A)R^(B)wherein R^(A) and R^(B) are independently a (C₁-C₆)alkyl group. In thecase where the substituent is phenyl or benzyl, the phenyl ring may besubstituted with any of the foregoing except phenyl or benzyl.

There are several actual or potential chiral centres in the compoundsaccording to the invention because of the presence of asymmetric carbonatoms. The presence of several asymmetric carbon atoms gives rise to anumber of diastereolsomers with R or S stereochemistry at each chiralcentre. The invention includes all such diastereoisomers and mixturesthereof. Currently, the preferred stereoconfiguration of the carbon atomcarrying the R₂ group is R; and that of the carbon atom carrying the R₁group (when asymmetric) is R.

In the compounds of the invention:

When Z is a radical of formula —N(OH)CH(═O), R₁ is hydrogen, methyl ortrifluoromethyl. When Z is a radical of formula —C(═O)NH(OH), R₁ ishydrogen, methyl, trifluoromethyl, hydroxy, halo (e.g. chloro, bromo orespecially fluoro) or amino. Hydrogen is currently preferred in bothcases.

R₂ may be, for example:

-   -   optionally substituted C₁-C₈ alkyl, C₃-C₆ alkenyl, C₃-C₆ alkynyl        or cycloalkyl;    -   phenyl(C₁-C₆ alkyl)-, phenyl(C₃-C₆ alkenyl)- or phenyl(C₃-C₆        alkynyl)- optionally substituted in the phenyl ring;    -   cycloalkyl(C₁-C₆ alkyl)-, cycloalkyl(C₃-C₆ alkenyl)- or        cycloalkyl(C₃-C₆ alkynyl)-optionally substituted in the        cycloalkyl ring;    -   heterocyclyl(C₁-C₆ alkyl)-, heterocyclyl(C₃-C₆ alkenyl)- or        heterocyclyl(C₃-C₆ alkynyl)-optionally substituted in the        heterocyclyl ring; or    -   CH₃(CH₂)_(p)O(CH₂)_(q)— or CH₃(CH₂)_(p)S(CH₂)_(q)—, wherein p is        0, 1, 2 or 3 and q is 1, 2 or 3.

Specific examples of R₂ groups include

-   -   methyl, ethyl, n- and iso-propyl, n- and iso-butyl, n-pentyl,        iso-pentyl 3-methyl-but-1-yl, n-hexyl, n-heptyl, n-octyl,        methylsulfanylethyl, ethylsulfanylmethyl, 2-methoxyethyl,        2-ethoxyethyl, ethoxymethyl, 3-hydroxypropyl, allyl,        3-phenylprop-3-en-1-yl, prop-2-yn-1-yl, 3-phenylprop-2-yn-1-yl,        3-(2-chlorophenyl)prop-2-yn-1-yl, but-2-yn-1-yl, cyclopentyl,        cyclohexyl, cyclopentylmethyl, cyclopentylethyl,        cyclopentylpropyl, cyclohexylmethyl, cyclohexylethyl,        cyclohexylpropyl, furan-2-ylmethyl, furan-3-ylmethyl,        tetrahydrofuran-2-ylmethyl, tetrahydrofuran-2-ylmethyl,        piperidinylmethyl, phenylpropyl, 4-chlorophenylpropyl,        4-methylphenylpropyl, 4-methoxyphenylpropyl, benzyl,        4-chlorobenzyl, 4-methylbenzyl, and 4-methoxybenzyl.

Presently preferred groups at R₂ are (C₁-C₆)alkyl-, cycloalkylmethyl-,(C₁-C₃)alkyl-S—(C₁-C₃)alkyl-, or (C₁-C₃)alkyl-O—(C₁-C₃)alkyl-,especially n-propyl, n-butyl, n-pentyl, cyclopentylmethyl,cyclopentylethyl, cyclohexylmethyl or cyclohexylethyl.

R₃ may be any of the groups discussed in relation to R₂, but presentlyit is preferred that R₃ is hydrogen.

Examples of groups R₄ are methyl, ethyl, n- and iso-propyl, n- andiso-butyl, n-pentyl, iso-pentyl, 3-methyl-but-1-yl, n-hexyl, n-heptyl,n-octyl, hydroxymethyl, 2-hydroxymethyl, methoxymethyl, 2-methoxyethyl,2-ethoxyethyl, 2-ethoxymethyl, 3-hydroxypropyl, allyl, cyclopentyl,cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylpropyl,cyclohexylmethyl, cyclohexylethyl, cyclohexylpropyl, furan-2-ylmethyl,furan-3-methyl, tetrahydrofuran-2-ylmethyl, tetrahydrofuran-2-ylmethyl,piperidinyl, piperazinyl, piperidinylmethyl, piperazinylmethyl, phenyl,4-chlorophenyl, 4-methylphenyl 4-methoxyphenyl, 4-hydroxyphenyl,4-aminophenyl, benzyl, 4-chlorobenzyl, 4-methylbenzyl, 4-methoxybenzyl,4-hydroxybenzy, 4-aminobenzyl, naphthyl, naphthylmethyl and naphthyl andnaphthylmethyl substituted in the naphthyl rings by methyl, methoxy,hydroxy, chloro, or amino.

When R₃ and R₄ taken together with the nitrogen to which they areattached form a heterocyclic ring, that ring may be, for examplepiperidino, piperazino, morpholino, pyridyl, oxazolyl, thiazolyl,oxadiazolyl, or thiadiazolyl, any of which may be substituted, forexample by methyl, methoxy, hydroxy, chloro, or amino.

Specific examples of compounds of the invention include

-   N-hydroxy-N-[2R-(3-naphthalen-1-ylmethyl-ureido)-hexyl]-formamide,-   N-[2R-(3-Benzyl-ureido)-hexyl]-N-hydroxy-formamide,-   N-{3-Cyclopentyl-2R-[3-(3,4-dimethoxy-benzyl)-ureido]-propyl}-N-hydroxy-formamide,-   N-{3-Cyclopentyl-2R-[3-pyridin-4-ylmethyl-ureido)-propyl]-N-hydroxy-formamide,-   N-{3-Cyclopentyl-2R-[3-(4-methoxy-benzyl)-ureido]-propyl-N-hydroxy-formamide,-   N-{3-Cyclopentyl-2R-[3-(4-methoxy-benzyl)-ureido]-propyl-N-hydroxy-formamide    and-   4-Phenyl-piperazine-1-carboxylic acid[1    R-cyclopentylmethyl-2-(formyl-hydroxy-amino)-ethyl]-amide    as well as the corresponding compounds in which the N-hydroxy    formylamino group is replaced by a hydroxamic acid group.

Compounds of the invention in which Z is an N-formylhydroxyamino groupmay be prepared by deprotecting an O-protected N-formyl-N-hydroxyaminocompound of formula (II):

in which R₁, R₂, R₃, and R₄ are as defined for general formula (I) andP₁ is a hydroxy protecting group removable to leave a hydroxy group byhydrogenolysis or hydrolysis. Benzyl is a preferred P₁ group for removalby hydrogenolysis, and tert-butyl and tetrahydropyranyl are preferredgroups for removal by acid hydrolysis.

Compounds of formula (II) may be prepared by reaction of a compound offormula (IVA)

with diphenylphosphoryl azide to form an intermediate compound offormula (IVB)

then reacting compound (IVB) with an amine of formula R₃R₄NH.

Compounds of formula (II) may also be prepared by N-formylation, forexample using acetic anhydride and formic acid, or1-formylbenzotriazole, of compounds of formula (III)

wherein R₁, R₂, R₃ and R₄ and P₁ are as defined in relation to formula(II).

Compounds (III) may be prepared by reaction of a carboxylic acid offormula (IV)

with diphenylphosphoryl azide to form an intermediate compound offormula (IVC)

then reacting compound (IVC) with an amine of formula R₃R₄NH.

Compounds of the invention in which Z is a hydroxamic acid group may beprepared by reacting the parent compound wherein Z is a carboxylic acidgroup (IIA)

with hydroxylamine or an N- and/or O-protected hydroxylamine, andthereafter removing any O- or N-protecting groups.

Compounds of formula (IIA) may be prepared by reaction of a carboxylicacid of formula (V)

with diphenylphosphoryl azide to form an intermediate compound offormula (VA)

then reacting compound (VA) with an amine of formula R₃R₄NH, thenremoving the protecting group P₁.

Further details of the preparation of compounds of the invention arepresented in the following Example, wherein the following abreviationsare used: Bn Benzyl DPPA Diphenylphosphoryl azide HPLC High performanceliquid chromatography LRMS Low resolution mass spectrometry RT Retentiontime TFA Trifluoroacetic acid

Analytical HPLC was run on a Beckman System Gold, using Waters SymmetryC18 column (50 mm, 4.6 mm) with 20 to 90% solvent B gradient (1.5ml/min) as the mobile phase. [Solvent A: 0.05% TFA in 10% water 90%MeCN; Solvent B: 0.05% TFA in 10% MeCN 90% water, 5 min gradient time],detection wavelength at 214 nm. Preparative HPLC was run on a Gilsonautoprep instrument using a C18 Waters delta pak (15 μm, 300 A, 25 mm,10 mm) with 20 to 90% solvent B gradient (6 ml/min) as the mobile phase.[Solvent A 10% MeCN/water; Solvent B: 10% water/MeCN, 13 min gradienttime], UV detection was at 214 nm. Reagents were purified and driedwhere necessary by standard techniques.

EXAMPLE 1

The preparation ofN-hydroxy-N-[2R-(3-naphthalen-1-ylmethyl-ureido)-hexyl]-formamide isoutlined in Scheme 1. 2R-[(Benzyloxy-formyl-amino)-methyl]-hexanoic acidwas prepared by analogy with methods in international patent applicationWO 99/39704.

-   Step A:    1-[1R-(benzyloxyamino-methyl)-pentyl]-3-naphthalen-1-ylmethyl-urea

A mixture of 2R-[(benzyloxy-formyl-amino)-methyl]-hexanoic acid (360 mg,1.3 mmol), DPPA (273 μl, 1.3 mmol) and triethylamine (180 μl, 1.3 mmol)in a solution of toluene (12 ml) were heated to 80° C. After 0.5 h1-naphthylmethylamine (433 μl, 2.6 mmol) was added and the reactionmixture was stirred for 18 h at 80° C. The mixture was allowed to cooland the solvent was removed in vacuo to yield an oily residue which wastaken up in dichloromethane (20 ml). The organic phase was washed with1M hydrochloric acid (2×20 ml), 1M sodium carbonate (2×20 ml), brine(1×20 ml), dried over anhydrous magnesium sulphate and the solvent wasremoved in vacuo to yield 1.0 g of a brown oil. Flash chromatography(dichloromethane, 3% methanol) yielded the title compound as a cloudyoil (100 mg, 18%). LRMS +ve: 406 (M+1, 100%). HPLC: RT 5.8 min (100%);¹H-NMR (CDCl₃) δ: 8.04 (1H, d, J=8.1 Hz), 7.88-7.84 (1H, m), 7.77-7.75(1H, m), 7.52-7.47 (2H, m), 7.39-7.13 (7H, m), 5.72 (1H, brs), 5.15 (1H,brs), 4.77 (2H, d, J=5.3 Hz), 4.40-4.38 (3H, m) 3.69 (1H, s), 2.98 (1H,dd, J=13.5 & 2.8 Hz), 2.70-2.66 (1H, m), 1.42-1.22 (6H, m), 0.95(3H, t,J=12.5 Hz).

-   Step B:    N-Benzyloxy-N-[2R-(3-naphthalen-1-ylmethyl-ureido)-hexyl]-formamide

To a solution of1-[1R-(benzyloxyamino-methyl)-pentyl]-3-naphthalen-1-ylmethyl-urea (94mg, 0.24 mmol) in dichloromethane (5 ml) was added formyl-aceticanhydride (63 ul, 0.72 mmol) and triethylamine (99 μl, 0.72 mmol) andthe reaction mixture was stirred for 18 h at room temperature. Thesolvent was removed in vacuo to yield the title compound as a clear oil(100 mg, 100%). No further purification was attempted. LRMS +ve: 434(M+1, 90%), 456 (M-1, 70%). HPLC: RT 6.2 min (95%).

-   Step C:    N-hydroxy-N-[2R-(3-naphthalen-1-ylmethyl-ureido)-hexyl]-formamide

To a solution ofN-benzyloxy-N-[2R-(3-naphthalen-1-ylmethyl-ureido)-hexyl]-formamide (100mg, 0.43 mmol) in ethanol (6 ml) was added Pd/C (25% w/w, 15 mg) and onedrop of formic acid and this suspension was then blanketed withhydrogen. The reaction mixture was stirred at room temperature for 18 h.The catalyst was filtered off and the solvent was removed under reducedpressure to yield an oil (77 mg). Preparative HPLC yielded the titlecompound as a clear oil (43 mg, 54%). HPLC: Rt 5.9 min (99%); LRMS, +veion 344 (M+1, 100%), 366 (M+Na, 80%); −ve ion 342 (M−1, 90%); ¹H-NMR(CDCl₃) δ: 10.00 (1H, brs, OH), 8.14 (1H, s, CHO), 7.91 (1H, d, J=8.4Hz, ArH), 7.81 (1H, d, J=7.9 Hz, ArH), 7.71 (1H, d, J=8.1 Hz, ArH),7.53-7.45 (2H, m, ArH), 7.37-7.26 (2H, m, ArH), 5.71 (1H, brs, NH), 5.37(1H, d, J=8.4 Hz, NH), 4.70 (2H, ddd, J=20.8 Hz, 15.1 Hz & 5.6 Hz),4.06-4.01 (1H, m), 3.76 (1H, dd, J=13.5 Hz & 11.6 Hz), 1.77-1.65 (1H,m), 1.53-1.26 (6H, m), 0.89 (3H, J=7.0 Hz, m); ¹³C-NMR; δ(CDCl₃): 14.2,22.8, 28.6, 32.2, 42.5, 47.1, 51.1, 123.5, 125.7, 125.8, 126.3, 126.8,128.6, 129.2, 131.5, 134.2, 134.5, 160.6, 163.4.

The following compounds may also be prepared by the method of Example 1

1. A compound of formula (I), or a salt or hydrate thereof:

wherein: Z represents a radical of formula —N(OH)CH(═O) or formula—C(═O)NH(OH); R₁ represents hydrogen, methyl or trifluoromethyl or,except when Z is a radical of formula —N(OH)CH(═O), a hydroxy, halo oramino group R₂ represents hydrogen or a group R₁₀-(D)_(n)-(ALK)_(m)-wherein R₁₀ represents an optionally substituted C₁-C₆ alkyl, C₂-C₆alkenyl, C₂-C₆ alkynyl, cycloalkyl, aryl, or heterocyclyl group and ALKrepresents a straight or branched divalent C₁-C₆ alkylene, C₂-C₆alkenylene, or C₂-C₆ alkynylene radical, and may be interrupted by oneor more non-adjacent —NH—, —O— or —S— linkages, D represents —NH—, —O—or —S—, and n is 0 or 1; R₃ and R₄ independently represent hydrogen or agroup R₁₀(D)_(n)(ALK)_(m)- as defined for R₂, or R₃ and R₄ takentogether with the nitrogen atom to which they are attached form anoptionally substituted monocyclic heterocyclic ring containing from 5 to7 ring atoms, one of which is the nitrogen atom to which R₄ and R₅ areattached and the remaining ring atoms being selected from compatiblecombinations of carbon, oxygen, sulfur and nitrogen.
 2. A method for thetreatment of bacterial infections in humans and non-human mammals, whichcomprises administering to a subject suffering such infection anantibacterially effective dose of a compound as claimed in claim
 1. 3. Acomposition comprising a compound as claimed in claim 1 and apharmaceutical acceptable carrier.
 4. A compound as claimed in claim 1,wherein Z is a radical of formula —N(OH)CH(═O), and R₁ is hydrogen,methyl or trifluoromethyl.
 5. A compound as claimed in claim 1, whereinZ is a radical of formula —C(═O)NH(OH), and R₁ is hydrogen, methyl,trifluoromethyl, hydroxy, halo or amino.
 6. A compound as claimed inclaim 1, wherein R₁ is hydrogen.
 7. A compound as claimed in claim 4wherein R₂ is: optionally substituted C₁-C₈ alkyl, C₃-C₆ alkenyl, C₃-C₆alkynyl or cycloalkyl; phenyl(C₁-C₆alkyl)-, phenyl(C₃-C₆alkenyl)- orphenyl(C₃-C₆alkynyl)- optionally substituted in the phenyl ring;cycloalkyl(C₁-C₆alkyl)-, cycloalkyl(C₃-C₆alkenyl)- orcycloalkyl(C₃-C₆alkynyl)-optionally substituted in the cycloalkyl ring;heterocyclyl (C₁-C₆ alkyl)-, heterocyclyl (C₃-C₆ alkenyl)- orheterocyclyl(C₃-C₆alkynyl)-optionally substituted in the heterocyclylring; or CH₃ (CH₂)_(p)O(CH₂)_(q)— or CH₃(CH₂)_(p)S(CH₂)_(q)—, wherein pis 0, 1, 2 or 3 and q is 1, 2 or
 3. 8. A compound as claimed in claim 7wherein R₂ is methyl, ethyl, n- or iso-propyl, n- and iso-butyl,n-pentyl, iso-pentyl 3-methyl-but-1-yl, n-hexyl, n-heptyl, n-octyl,methylsulfanylethyl, ethylsulfanylmethyl, 2-methoxyethyl, 2-ethoxyethyl,ethoxymethyl, 3-hydroxypropyl, allyl, 3-phenylprop-3-en-1-yl,prop-2-yn-1-yl, 3-phenylprop-2-yn-1-yl, 3-(2-chlorophenyl)prop-2-yn-1-yl, but-2-yn-1-yl, cyclopentyl, cyclohexyl,cyclopentylmethyl, cyclopentylethyl, cyclopentylpropyl,cyclohexylmethyl, cyclohexylethyl, cyclohexylpropyl, furan-2-ylmethyl,furan-3-ylmethyl, tetrahydrofuran-2-ylmethyl,tetrahydrofuran-2-ylmethyl, piperidinylmethyl, phenylpropyl,4-chlorophenylpropyl, 4-methylphenylpropyl, 4-methoxyphenylpropyl,benzyl, 4-chlorobenzyl, 4-methylbenzyl, or 4-methoxybenzyl.
 9. Acompound as claimed in claim 7 wherein R₂ is (C₁-C₆)alkyl-,cycloalkylmethyl-, (C₁-C₃)alkyl-S—(C₁-C₃)alkyl-, or(C₁-C₃)alkyl-O—(C₁-C₃) alkyl-, especially n-propyl, n-butyl, n-pentyl,cyclopentylmethyl, cyclopentylethyl, cyclohexylmethyl orcyclohexylethyl.
 10. A compound as claimed in claim 4 wherein R₃ is anyof the R₂ groups specified in claim 7, 8 or
 9. 11. A compound as claimedin claim 4 wherein R₃ is hydrogen.
 12. A compound as claimed in claim 4wherein R₄ is methyl, ethyl, n-or iso-propyl, n-or iso-butyl, n-pentyl,iso-pentyl, 3-methyl-but-1-yl, n-hexyl, n-heptyl, n-octyl,hydroxymethyl, 2-hydroxymethyl, methoxymethyl, 2-methoxyethyl,2-ethoxyethyl, 2-ethoxymethyl, 3-hydroxypropyl, allyl, cyclopentyl,cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylpropyl,cyclohexylmethyl, cyclohexylethyl, cyclohexylpropyl, furan-2-ylmethyl,furan-3-methyl, tetrahydrofuran-2-ylmethyl, tetrahydrofuran-2-ylmethyl,-piperidinyl, piperazinyl, piperidinylmethyl, piperazinylmethyl, phenyl,4-chlorophenyl, 4-methylphenyl 4-methoxyphenyl, 4-hydroxyphenyl,4-aminophenyl, benzyl, 4-chlorobenzyl, 4-methylbenzyl, 4-methoxybenzyl,4-hydroxybenzy, 4-aminobenzyl, naphthyl, naphthylmethyl and naphthyl andnaphthylmethyl substituted in the naphthyl rings by methyl, methoxy,hydroxy, chloro, or amino.
 13. A compound composition as claimed in anyof as claimed in claim 4 wherein R₃ and R₄ taken together with thenitrogen to which they are attached form a piperidino, piperazino,morpholino, pyridyl, oxazolyl, thiazolyl, oxadiazolyl, or thiadiazolylring, any of which may be substituted.